Tape recording and reproducing systems for use as computer data storage devices are required to provide increasingly high data transfer rates and to perform a read verification upon all data being written to tape. Streaming tape drives are so named because multiple blocks of user data are typically written to tape in a single streaming operation, rather than as a series of start-stop operations. Digital linear tape drives are an improved species of streaming tape drives.
In order to increase data density in streaming tape drive systems, track widths are decreasing, while data transfer rates are increasing. It is practical to provide e.g. approximately 128 linear data tracks within a one-half inch wide tape with current technology. One way to increase track densities is to employ azimuth recording techniques in which the tape head structure is canted at a particular offset angle relative to longitude and direction of travel of the tape. At the same time, the digital linear tape drive should be backwardly compatible with tapes which may have been recorded with conventional longitudinal recording techniques. Azimuth recording technology, together with a continuing requirement for backward compatibility, has resulted in tape head structures which include a higher number of write elements, and has required a more complex head positioning mechanism which provides both transverse (up and down) as well as azimuth angle positioning of the tape head structure.
With a relatively high number of narrow-width data tracks, great care must be taken in accurately positioning the tape head structure and in providing efficient electronics for amplifying signals read back by read elements from the tape, and for driving write head elements with signals to be written to the tape. Also, interconnecting read and write data signals between a tape head array and associated electronics poses several concerns. These concerns include susceptibility to electrical noise and crosstalk between channels, parasitic capacitance and inductance, mechanical forces unwantedly applied to the head positioning mechanism, cabling and manufacturing costs, head maintenance and upgrades, and availability of circuit board space.
Flex circuits have been used in the mass storage art to provide flexible electrical connections to magnetic recording/playback heads. Flex circuits have been frequently employed in hard disk drives to provide flexible circuit connections, as well as a mounting substrate for carrying discrete and integrated electronics circuitry in order to position playback preamplifier circuitry close to the read head elements in order to improve signal to noise ratios. One example of a flex circuit for a hard disk drive employing a rotary voice coil head positioner is given in U.S. Pat. No. 5,055,969 to Putnam, entitled: "Servo/Data Actuator Arm Flexible Circuit", the disclosure being incorporated herein by reference.
Flexible substrates providing flexible circuit paths have also been proposed for use with tape recording systems. Examples include U.S. Pat. No. 5,134,252 to Himeno et al., entitled: "Signal Line", and U.S. Pat. No. 5,051,366 to Anderson et al, entitled: Electrical Connector". The Himeno et al. patent describes a flexible circuit carrying magnetically shielded signal paths between a rotary head drum of a digital audio tape recorder and external read preamplifier/write driver circuitry. The Anderson et al. patent describes a connector mechanism for interconnecting flexible circuits of a tape head module to flexible circuits extending from separate read and write circuit cards of e.g. an IBM 3490 Tape Drive. While these patents suggest the use of flexible circuits within tape drives, they do not overcome or suggest any solutions to a number of serious problems confronting streaming tape drives for azimuth as well as longitudinal recording, achieved with a multi-dimension positionable head structure.